When closing and opening screw lids on food containers, a user generally holds the container in one hand and the screw lid in the opposite hand and applies a relative torque between the container and screw lid. Typically, a clockwise torque is applied to close a screw lid, and an anti-clockwise torque is applied to open a screw lid.
Users may find it difficult to open screw lids that have been fitted by themselves, other users or mechanical processes such as when a food container is filled by a food manufacturer. Indeed, food containers may be vacuum sealed, which may result in an increased torque required to open the container for the first time after it is bought. The problem of opening food container lids may be experienced by the elderly or infirm in particular. Users of this type may not have the grip strength required to apply the requisite torque.